Digital image processing apparatus and method of controlling the same

ABSTRACT

A digital image processing apparatus and a method of controlling the same. When the composition of a subject displayed on a display of the apparatus is changed during application of a first shutter-release signal, a current auto-focus (AF) region moves along with the subject and displayed on the display at the same time as the subject. The apparatus can further display an initial AF region on the display in a manner distinguishable from the current AF region. After the composition of the subject is changed, while the current AF region moving along with the subject is being displayed on the display, when the application of the first shutter-release signal is interrupted, an AF region is reset as the initial AF region. Also, an image file can be generated and stored after application of a second-shutter release signal which occurs after application of the first shutter-release signal.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application is a continuation application of and claims thepriority benefit of U.S. patent application Ser. No. 12/231,780, filedon Sep. 5, 2008, now U.S. Pat. No. 8,300,135, and also claims thepriority benefit of Korean Patent Application No. 10-2008-0011064, filedon Feb. 4, 2008, in the Korean Intellectual Property Office, the entirecontents of all of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a digital image processing apparatusand a method of controlling the same. More particularly, the presentinvention relates to a digital image processing apparatus and method inwhich the current AF region is displayed on a display unit if thecomposition of a subject is changed with application of a firstshutter-release signal, while a current auto-focus (AF) region is movingalong with the subject.

2. Description of the Related Art

In general, digital image processing apparatuses process images ofdigital cameras, personal digital assistants (PDAs), phone cameras, andpersonal computer (PC) cameras or employ motion recognition sensors. Adigital image processing apparatus may receive a desired image via aphotographing device, display the received image on an image displaydevice, store the image as an image file by selection of a user, andprint the stored image file.

The digital image processing apparatus extracts data required for autofocus (AF) from a predetermined region in order to enable an AFfunction. In this case, selection of a region is limited as shown inFIGS. 1A and 1B. Specifically, a previously determined region may beselected or center AF or multi-AF may be selected. Also, beforephotographing an image, a complicated process including selecting amenu, selecting a region selection menu, and selecting a region isperformed.

FIG. 1A is a bottom view of an example of a digital camera forexplaining a center AF method. In the center AF method, a screen isdivided into a plurality of fixed regions, a predetermined region isselected from the fixed regions, AF processing is performed on theselected region, and photographing occurs.

FIG. 1B is a bottom view of an example of a digital camera forexplaining a multi-AF method. In the multi-AF method, a screen isdivided into a plurality of fixed regions, AF processing is performed onthe respective fixed regions, and photographing occurs.

Since the methods used in the digital cameras shown in FIGS. 1A and 1Bare complicated, when a user adjusts the focus centering on selection ofa region, after the focus is adjusted by pressing an AF lock button, thedigital camera is moved to a desired region to adjust the focus and thenmoved to obtain a desired composition before photographing begins. Also,when AF is performed using a touch pad as shown in FIG. 1C, it isconvenient for photographers, but a liquid crystal display (LCD) for thetouch pad is necessarily required.

As described above, a conventional digital image processing apparatus islimited in selecting an AF region. Also, the digital image processingapparatus moves from a predetermined region to another region only byoperating a button, so that it is difficult to set the AF region.

SUMMARY OF THE INVENTION

The present invention provides a digital image processing apparatus andmethod in which the current AF region is displayed on a display unit ifthe composition of a subject is changed with application of a firstshutter-release signal, while a current auto-focus (AF) region is movingalong with the subject, so that a user can easily set a desired AFregion.

According to an aspect of the present invention, there is provided adigital image processing apparatus having a display unit. The apparatusincludes a digital signal processing unit for controlling the digitalimage processing apparatus such that after the composition of a subjectis changed during application of a first shutter-release signal, acurrent AF region moves along with the subject and is displayed on thedisplay unit at the same time.

An initial AF region may be further displayed on the display unit.Before the composition of the subject is changed, the composition of thesubject may be set such that the subject is located within the initialAF region. While the composition of the subject is being changed and thecurrent AF region moving along with the subject is being displayed onthe display unit, the digital signal processing unit may control thedigital image processing apparatus such that the initial AF regionremains displayed on the display unit.

The digital signal processing unit may control the digital imageprocessing apparatus such that the current AF region and the initial AFregion are distinguishingly displayed on the display unit. The currentAF region and the initial AF region may be distinguishingly displayed byvarying at least one of color, shape, and thickness of a region divisionline. After the composition of the subject is changed, while the currentAF region moving along with the subject is being displayed on thedisplay unit, when the application of the first shutter-release signalis interrupted, the digital signal processing unit may reset an AFregion as the initial AF region.

Another embodiment of the present invention provides a method ofcontrolling a digital image processing apparatus comprising a displayunit. The method includes setting the composition of a subject such thatthe subject is disposed in an initial auto-focus (AF) region, inputtinga first shutter-release signal; changing the composition of the subjectduring the application of the first shutter-release signal, moving acurrent AF region along with the subject and displaying the current AFregion on the display unit at the same time, inputting a secondshutter-release signal, and generating and storing an image file.

During the changing of the composition of the subject during theapplication of the first shutter-release signal and during the moving ofthe current AF region along with the subject and the displaying of thecurrent AF region on the display unit at the same time, the initial AFregion may remain displayed on the display unit. The current AF regionand the initial AF region may be distinguishingly displayed on thedisplay unit.

The current AF region and the initial AF region may be distinguishinglydisplayed by varying at least one of color, shape, and thickness of aregion division line. During the changing of the composition of thesubject during the application of the first shutter-release signal andduring the moving of the current AF region along with the subject andthe displaying of the current AF region on the display unit at the sametime, when the application of the first shutter-release signal isinterrupted, an AF region may be reset as the initial AF region. Movingthe current AF region along with the subject and displaying the currentAF region on the display unit at the same time may include moving thecurrent AF region along with the subject and displaying a moving path ofthe current AF region on the display unit in real-time.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings in which:

FIGS. 1A through 1C are bottom views of an example of a digital imageprocessing apparatus for explaining conventional methods of selectingregions;

FIG. 2 is a perspective view of a front side and a top side of anexample of a digital image processing apparatus according to anembodiment of the present invention;

FIG. 3 is a bottom view of the digital image processing apparatus shownin FIG. 2;

FIG. 4 is a block diagram of the digital image processing apparatusshown in FIGS. 2 and 3;

FIG. 5 is a diagram for explaining an example of an operation ofphotographing images using a digital image processing apparatusaccording to an embodiment of the present invention;

FIGS. 6A through 6E are diagrams for explaining an example of a processof photographing an image using a digital image processing apparatusaccording to an exemplary embodiment of the present invention; and

FIG. 7 is a flowchart illustrating an example of a method of controllinga digital image processing apparatus according to an exemplaryembodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 2 is a perspective view of a front side and a top side of anexample of a digital image processing apparatus according to anembodiment of the present invention.

Referring to FIG. 2, the digital image processing apparatus includes ashutter-release button 101, a power button 103, a flash 105, a sub-light107, and a lens 109. When the power button 103 is pressed, power issupplied to the digital image processing apparatus so that the digitalimage processing apparatus can operate. In this state, when theshutter-release button 101 is pressed, a charge-coupled device (CCD) ora film is exposed to light for a predetermined time via an irisdiaphragm (not shown) and the lens 109 so that an image of a subject tobe photographed is recorded in the CCD.

When the shutter-release button 101 is pressed by a user, first andsecond image photographing signals are generated. When theshutter-release button 101 is half-pressed, the digital image processingapparatus adjusts the focus and controls the amount of light enteringthe lens 109. When the focus is properly adjusted, a green light lightsup on a display unit (refer to 113 in FIG. 3). After the focus isadjusted and the amount of light is controlled by half-pressing theshutter-release button 101, the shutter-release button 101 is fullypressed to photograph the subject.

The flash 105 is used to instantaneously or substantiallyinstantaneously illuminate the subject when photographing takes place ina dark place. Flash modes include an automatic mode, a forced flashmode, a flash-off mode, a red-eye reduction mode, and a slow-sync flashmode.

The sub-light 107 supplies light to the subject such that in the case ofa lack of light or night photography, the digital image processingapparatus can automatically adjusts the focus in a rapid and accurateway. The lens 109 receives light bouncing off the subject and processesan image of the subject.

FIG. 3 is a view of a back side of the digital image processingapparatus shown in FIG. 2.

Referring to FIG. 3, the digital image processing apparatus furtherincludes a wide-angle zoom button 111 w, a telephoto zoom button 111 t,the display unit 113, and input buttons B1 to B14 (hereinafter, referredto as ‘buttons B1 to B14’), wherein each button may include a touchsensor (not shown) or a contact switch (not shown).

The wide-angle zoom button 111 w or the telephoto zoom button 111 t ispressed to respectively increase or decrease an angle of view, therebychanging the size of a selected region to be photographed. When thewide-angle zoom button 111 w is pressed, the size of the selected regionis reduced. When the telephoto zoom button 111 t is pressed, the size ofthe selected region is enlarged.

The buttons B1 to B14 are arranged in a column and a row beside thedisplay unit 113. Each of the buttons B1 to B14 arranged along thelateral and bottom sides of the display unit 113 includes the touchsensor or the contact switch. If each of the buttons B1 to B14 includesa touch sensor, each of the buttons B1 to B17 arranged in a row or eachof the buttons B8 to B14 arranged in a column is touched and movedupward, downward, to the left, or to the right, so that an arbitraryvalue (e.g., color or brightness) may be selected out of main menu iconsor one of sub-menu icons included in the main menu icons may be enabled.If each of the buttons B1 to B14 includes a contact switch, a main menuicon and a sub-menu icon can be directly selected to perform a desiredfunction. When touch sensors are used, the operating force is smallerthan the operating force for contact switches, and the contact switchneeds to be touched more strongly than the touch sensor.

FIG. 4 is an exemplary block diagram of the digital image processingapparatus shown in FIGS. 2 and 3.

Referring to FIG. 4, the digital image processing apparatus includes thedisplay unit 113, a user input unit 121, an image photographing unit123, an image processing unit 125, a storage unit 127, and a digitalsignal processing unit 129. The user input unit 121 includes the shutterrelease button 101, the power button 103, the wide-angle zoom button 111w and the telephoto zoom button 111 t, and buttons B1 to B14. Theshutter-release button 101 is operated to expose a CCD to light for apredetermined time. The power button 103 is pressed to supply power tothe digital image processing apparatus. The wide-angle zoom button 111 wor the telephoto zoom button 111 t is pressed to increase or decrease anangle of view. The buttons B1 to B14 are arranged in a row and a columnbeside the display unit 113. Each of the buttons B1 to B14 may include atouch sensor (not shown) or a contact switch (not shown).

The image photographing unit 123 includes a shutter, a lens, an irisdiaphragm, the CCD, and an analog-to-digital converter (ADC), althoughthey are not shown. The shutter is a component that controls the amountof light entering the lens and the iris diaphragm. The lens receiveslight bouncing off a subject to be photographed and processes an imageof the subject. In this case, the amount of light is controlledaccording to an opening extent of the iris diaphragm, which is regulatedby the digital signal processing unit 129.

The CCD accumulates light received via the lens and outputs an image onthe display unit 113 according to the amount of accumulated light inresponse to a vertical synchronizing signal. The CCD converts lightreflected by a subject to be photographed into an electric signal. Inorder to obtain a color image using the CCD, a color filter is includedin the digital image processing apparatus of the present invention. Thecolor filter may be a color filter array (CFA). The CFA includesregularly arranged pixels, each pixel allowing only single-color lightto pass therethrough, and may have various shapes according to the typeof arrangement of pixels. The ADC converts an analog image signal outputfrom the CCD into a digital signal.

The image processing unit 125 processes raw digital data so as todisplay the data. The image processing unit 125 removes a black levelcaused by a dark current generated in the CCD and CFA, which aresensitive to temperature variations. The image processing unit 125 gammaencodes data in conformity with nonlinearity of a human's eyesight. Theimage processing unit 125 converts a Bayer pattern embodied by an RGRGline and a GBGB line of the gamma encoded data into an RGB line usingCFA interpolation. The image processing unit 125 converts aninterpolated RGB signal into a YUV signal, performs an edge compensationprocess of filtering a Y signal using a high pass filter (HPF) toprocess an image clearly, performs a color correction process ofcorrecting color values of U and V signals using a normal colorcoordinate system, and eliminates noise from Y, U, and V signals. Theimage processing unit 125 compresses and processes the Y, U, and Vsignals, from which noise is eliminated, to generate a jointphotographic coding experts group (JPEG) file, and the generated JPEGfile is displayed on the display unit 113 and stored in the storage unit127. The above-described operations of the image processing unit 125 arecontrolled by the digital signal processing unit 129. While a firstshutter-release signal is being applied to the digital image processingapparatus, when the composition of a subject is changed, the digitalsignal processing unit 129 controls the digital image processingapparatus such that a current auto focus (AF) region moves along withthe subject and is displayed on the display unit 113 at the same time.

FIG. 5 is a diagram for explaining an operation of photographing imagesusing a digital image processing apparatus 100 according to anembodiment of the present invention. In FIG. 5, a first subject P1, asecond subject P2, and a third subject P3 are sequentially disposed on afront side of the digital image processing apparatus 100.

FIGS. 6A through 6E are diagrams for explaining an example of a processof photographing an image using a digital image processing apparatus 100according to an exemplary embodiment of the present invention. In FIGS.6A through 6E, it is exemplarily illustrated that although a user of thedigital image processing apparatus 100 disposes the second subject P2 inthe center of an image in order to photograph all the three subjects P1,P2, and P3 in the image, the user tries focusing the lens 109 on thefirst subject P1.

As will now be discussed in more detail, the digital image processingapparatus 100 operating in accordance with embodiments of the presentinvention may allow the user to easily set a desired region as the AFregion. Specifically, an example of a method of controlling the digitalimage processing apparatus shown in FIG. 4 will be described withreference to FIG. 7. In this present embodiment, an algorithm foroperating the digital image processing apparatus may be performed in thedigital signal processing unit 129 by the aid of peripheral components.

Referring to FIG. 7, the method of controlling the digital imageprocessing apparatus shown in FIG. 4 includes setting the composition ofa subject (operation S110), inputting a first shutter-release signal(operation S120), determining if the application of the firstshutter-release signal is continued (operation S130), changing thecomposition of the subject (operation S140), determining if theapplication of the first shutter-release signal is continued (operationS150), moving a current AF region along with the subject and displayingthe current AF region on a display unit at the same time (operationS160), determining if the application of a first shutter-release signalis continued (operation S170), inputting a second shutter-release signal(operation S180), and generating and storing an image file (operationS190).

To begin, the user sets the composition of the subject in operationS110. Specifically, while seeing a preview image displayed on thedisplay unit 113, the user controls the position and size of the subjectto be photographed in the image. In FIGS. 5 and 6, although the secondsubject P2 is disposed in the center of the image and photographed inorder to photograph a single image containing all the three subjects P1,P2, and P3, the focus of the image is adjusted to the first subject P1.

In a conventional digital image processing apparatus, a user adjusts thefocus centering on selection of a region. Thus, after the focus isadjusted by pressing an AF lock button, a digital camera is moved to adesired region to adjust the focus and then moved to obtain a desiredcomposition before photographing begins. During this complicatedprocess, an initial AF region located in the center of a display unitand a current AF region on which the user desires to focus a lens arenot distinguishingly displayed. Thus, it is basically impossible toconfirm where the current AF region is during the movement of thedigital camera.

In order to solve the foregoing problems, in the digital imageprocessing apparatus 100 according to the embodiment of the presentinvention, a subject on which the user desires to focus the lens 109 isdisposed in the initial AF region AF1. Thereafter, while the firstshutter-release signal is being applied, when the composition of thesubject is changed by moving the digital image processing apparatus 100,the current AF region AF2 moves along with the subject and is displayedon the display unit 113 at the same time.

Specifically, FIG. 6A illustrates that the composition of the subjectsP1 to P3 is determined such that the first subject P1 is disposed in theinitial AF region AF1. That is, when the user desires to dispose thesecond subject P2 in the center of an image and focus the lens 109 onthe first subject P1, the composition of the image is determined suchthat the first subject P1 is disposed in the initial AF region AF1. Inthis state, the initial AF region AF1 corresponds to the current AFregion AF2.

Although FIG. 6A illustrates that the initial AF region AF1 is set tothe center of the display unit 113, the present invention is not limitedto this arrangement. That is, the initial AF region AF1 may be set tovarious regions of the display unit 113 according to a user's selectionor automatically.

Next, the user inputs the first shutter-release signal and changes thecomposition of the subjects P1 to P3 during the application of the firstshutter-release signal. Thus, the current AF region AF2 moves along withthe first subject P1 and is displayed on the display unit 113 at thesame time.

Specifically, FIG. 6B illustrates that the composition of the subjectsP1 to P3 is changed during the application of the first shutter-releasesignal, and FIG. 6C illustrates that when the composition of thesubjects P1 to P3 is changed, the current AF region AF2 moves along withthe subject and is displayed on the display unit 113. During theapplication of the first shutter-release signal, the user moves thedigital image processing apparatus 100 in the arrow direction to changethe composition of the subjects P1 to P3 such that the second subject P2is disposed in the center of the image.

As a result, as shown in FIGS. 6B and 6C, the current AF region AF2moves along with the first subject P1, which is determined to bedisposed in the initial AF region AF1, and is displayed on the displayunit 113 at the same time during the application of the firstshutter-release signal. While the composition of the subjects P1 to P3is changed and the current AF region AF2 moving along with the firstsubject P1 is displayed on the display unit 113, the digital signalprocessing unit 129 may control the digital image processing apparatus100 such that the initial AF region AF1 remains displayed on the displayunit 113. In other words, the initial AF region AF1 that is determineddirectly before or when the first shutter-release signal is inputremains displayed irrespective of the motion of the current AF regionAF2. Obviously, the initial AF region AF1 displayed on the display unit113 is not a region on which the lens 109 is actually focused but an AFregion set as a default.

The digital image processing unit 129 may control the digital imageprocessing apparatus 100 such that the current AF region AF2 and theinitial AF region AF1 are distinguishingly displayed on the display unit113. Specifically, as shown in FIGS. 6B and 6C, the initial AF regionAF1 may be distinguished from the current AF region AF2 by varying atleast one of the color, shape, and thickness of a region division line.In FIGS. 6B and 6C, the initial AF region AF1 is illustrated with a graydotted line, and the current AF region AF2 is illustrated with a greensolid line.

After the composition of the subject is changed during the applicationof the first shutter-release signal in operation S140, while the currentAF region AF2 is moving along with the first subject P1 and beingdisplayed on the display unit 113 at the same time in operation S160,the digital signal processing unit 129 continuously determines if theapplication of the first shutter-release signal is continued inoperations S130, S150, and S170.

That is, referring to FIG. 6D, when the user inputs a secondshutter-release signal, while the lens 109 is being focused on the firstsubject P1, an image in which the second subject P2 is disposed in thecenter may be photographed. However, after the composition of thesubjects P1 to P3 is changed, while the current AF region AF2 movingalong with the first subject P1 is displayed on the display unit 113,the application of the first shutter-release signal may be interrupted.In this case, the initial AF region AF1 is reset as an AF region. Thatis, when the application of the first shutter-release signal isinterrupted, as shown in FIG. 6E, the initial AF region AF1 is reset asthe AF region and becomes the current AF region AF2 again.

In other words, when it is determined that the application of the firstshutter-release signal is interrupted, the initial AF region AF1 isreset as an AF region in operations S135, S155, and S175 shown in FIG.7. When the application of the first shutter-release signal isinterrupted, as shown in FIG. 6E, the initial AF region AF1 is reset asthe AF region and becomes the current AF region AF2 again.

Finally, when the user sets a desired composition of the subject, theuser inputs the second shutter-release signal in operation S180, and thedigital signal processing unit 129 receives the second shutter-releasesignal and controls the image processing unit 125 to generate aphotographed image as a JPEG image file, display the photographed imageon the display unit 113, and store the JPEG image file in the storageunit 127 in operation S190.

Accordingly, as can be appreciated from the above, the digital imageprocessing apparatus 100 may allow the user to easily set a desiredregion as the AF region.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby one of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

What is claimed is:
 1. A digital image processing apparatus comprising:an image receiving unit that obtains an image of a subject; a displayunit; and a processing unit configured to: display an auto-focus (AF)region on the display unit in a position as an initial AF region; adjusta focus corresponding to the subject at the current AF region uponreceiving an auto-focus lock signal; control the current AF region totrack the subject when the subject is in motion while the auto-focuslock signal is applied; display the current AF region tracking thesubject on the display unit; and while the current AF region trackingthe subject is displayed on the display unit, when a state of theauto-focus lock signal is changed, reset a position of the current AFregion tracking the subject as the initial AF region.
 2. The apparatusof claim 1, wherein the current AF region tracking the subject isdisplayed as superimposed on the subject on the display unit.
 3. Theapparatus of claim 1, wherein before the AF region tracks the subject,the subject is focused within the initial AF region of the display unit.4. The apparatus of claim 1, wherein while the current AF regiontracking the subject is displayed on the display unit, the processingunit is configured to display the initial AF region on the display unit.5. The apparatus of claim 4, wherein the processing unit is furtherconfigured to display the current AF region in a different manner fromthe initial AF region on the display unit.
 6. The apparatus of claim 5,wherein the AF region tracking the subject and the initial AF region aredistinguishably displayed by showing at least one variation of a color,a shape, and thickness of a focus boundary line.
 7. The apparatus ofclaim 1, wherein the processing unit generates and stores an image fileupon receiving a shutter-release signal which occurs after receiving theauto-focus lock signal.
 8. A method of controlling a digital apparatuscomprising a display unit, the method comprising: obtaining an image ofa subject through an image receiving unit of the digital apparatus;displaying a current auto-focus (AF) region superimposed on the image ofthe subject on the display unit of the digital apparatus as an initialAF region; receiving an input auto-focus signal; adjusting a focuscorresponding to the subject at the current AF region upon receiving theauto-focus lock signal; controlling the current AF region to track thesubject when the subject is in motion while the auto-focus lock signalis received; displaying the current AF region tracking the subject onthe display unit as the subject moves; receiving an inputshutter-release signal after the current AF region tracks the subjectaway from the initial AF region; generating and storing an image file inresponse to receiving the shutter-release signal; and during thetracking of the subject by the current AF region, when a state of theauto-focus lock signal is changed, resetting the current AF regiontracking the subject as the initial AF region.
 9. The method of claim 8,wherein the current AF region tracks the subject during receiving theauto-focus lock signal, and during the tracking of the subject by thecurrent AF region, the initial AF region also remains displayed on thedisplay unit.
 10. The method of claim 8, wherein the current AF regiontracking the subject and the initial AF region are distinguishablydisplayed on the display unit.
 11. The method of claim 10, wherein thecurrent AF region tracking the subject and the initial AF region aredistinguishably displayed by varying at least one of color, shape, andthickness of a focus boundary line.
 12. The method of claim 8, whereinthe current AF region tracking the subject comprises displaying a movingpath of the current AF region tracking the subject on the display unitin real-time.
 13. A method for controlling a digital apparatuscomprising a display, the method comprising: displaying an image of asubject on a display; displaying an initial auto-focus (AF) region onthe display; displaying an auto-focus (AF) region tracking the subjecton the display while continuing to display the AF region tracking thesubject superimposed on the subject and continuing to display theinitial AF region as a composition of the subject changes duringreceiving of an auto-focus lock signal; and after the composition of thesubject changes and while the AF region tracking the subject isdisplayed on the display, when a state of the auto-focus lock signal ischanged, resetting the AF region tracking the subject as the initial AFregion.
 14. The method of claim 13, wherein the AF region tracking thesubject and the initial AF region are distinguishably displayed on thedisplay.
 15. The method of claim 13, further comprising generating andstoring an image file after receiving an input shutter-release signalwhich occurs after receiving the input auto-focus lock signal.